add mouse service to manage mouse position

avoid creating a new service if one already exists

add fork system call

kernel await / fire event: add code to wait for specific event

usb mouse: report summed position

stdio: add negative sigh for printing negative numbers

fix compiler errors (shift count overflow)

usb xhci: continously print mouse report data

usb xhci: initiate interrupt IN transfer

usb xhci: send configure endpoint command to set up endpoints

usb: show configuration and interface information

usb: hlib: use "unsafe" direct event calls to work without strings

usb refactoring: no more xhci-specific code in main usb.h file

usb : print usb version

shell: don't even try to create a "" program without a name

xhci refactoring: sperate out all xhci-related code to its own directory

xhci: refactoring: move out xhci controller code

make printf function available for not-main userland files

xhci: refactoring: use SlotXHCI instead of long parameter list

xhci: refactor and seperate out commands

xhci: refactor trbRing functions to seperate file

vga: add scrolling when exceeding maximum default line count

shell / ioManager: don't allow backspace when input buffer is empty

fix issue #3: crash when running an unknown program

xhci: show device information using usb strings

xhci: print basic usb device information

xhci: clean up slot initialization

xhci: send get device information command to attached usb devices

xhci: configure endpoint

xhci: send address device command